Expert Data Companies
The vendors that hire engineers, attorneys, scientists and physicians to write and grade AI training data, sorted by field. Each entry repeats only what the vendor publishes, checked November 7, 2026.
Software and coding
Seven vendors whose published services include code, from written demonstrations to tasks scored by automated verifiers. None publishes a buyer price; each quotes per project. Full software page.
| Vendor | What its own pages describe | Published detail | How you buy |
|---|---|---|---|
| Surge AI | Sells labs preference data, written demonstrations, rubrics, verifiers and human evals, plus ready-made expert datasets; also builds RL environments. | Works in more than 70 languages, by its own count | Managed service |
| Turing | Supplies labs with post-training and evaluation data. Its RL environments include working replicas of the Jira, Salesforce and Zendesk interfaces, and MCP back ends. | Not published | Managed service |
| Appen | Listed on the ASX. Offers labeling and LLM post-training data, and a catalog of RL tasks scored by verifiers. | 500 coding tasks on offer, every one with its own automatic checker | Managed service |
| Toloka | Managed data company headquartered in Amsterdam. Its menu: SFT demonstration data, RLHF/DPO preference comparisons, machine-checkable eval and RL tasks, and red-team work. | Not published | Managed service |
| micro1 | Finds, screens and manages specialists whose output is post-training and reinforcement learning data for model builders. | Not published | Managed service |
| Snorkel AI | Pitches an expert data service to labs and large companies (custom datasets, benchmarks, evals) and builds bespoke agent systems too. | Not published | Platform plus services |
| Mercor | Hires out its network of experts for human evals and expert-written training sets; also publishes the APEX benchmarks and builds RL environments. | Not published | Managed service |
Disclosure: a vendor in this table could pay us a fee should one of our introductions turn into a contract. Inclusion, order and wording here are not for sale.
Free for buyers. We name our suggested vendor to you before contacting it.
Which credential should each field require?
Vendors rarely list the professions they cover, so the useful question is what evidence of expertise to ask for. Most licensed professions can be checked on a public registry in a minute.
Law
Contract redlines, case-law reasoning, statutory questions and grading model answers against a rubric written by a practicing attorney. Expert networks such as Mercor, micro1 and Handshake AI describe recruiting experts in general terms; none of the pages we read names law as a field or explains bar checks, so ask. Law and finance vendors.
| Credential asked for | How to check it yourself |
|---|---|
| US-licensed attorney | Bar admission and good standing on the public attorney search of the state that licensed them. Admission in one state says nothing about another. |
| JD graduate or law student | Degree or enrollment verification through the school or a clearinghouse. Not a licensed lawyer; say so in the rubric. Lookup: National Student Clearinghouse. |
| Paralegal or contracts specialist | Usually no state license. Ask for years in the role and a graded sample task. |
Finance
Financial modeling, filings analysis, accounting treatment and audit-style review of model outputs. A license matters for some tasks (tax, audit, advice) and not for others (modeling).
| Credential asked for | How to check it yourself |
|---|---|
| CPA | License status in the issuing state, searchable for most states through CPAverify. Lookup: CPAverify (NASBA). |
| Registered representative | Registration and disclosure history on FINRA BrokerCheck. Lookup: FINRA BrokerCheck. |
| Investment adviser representative | Registration on the SEC adviser disclosure site. Lookup: SEC Investment Adviser Public Disclosure. |
| Analyst or banker, no license | Employment history and a graded modeling or memo task. Ask whether the vendor checks references. |
Science
Graduate-level problems in physics, chemistry, biology and math, written with worked solutions, and expert grading of model reasoning.
Medicine
Clinical questions written and graded by physicians and nurses, as expertise only. Nothing here involves patient records.
Science and medicine vendors| Credential asked for | How to check it yourself |
|---|---|
| PhD or doctoral candidate | Degree verification through the university or a clearinghouse; ask which department and year. Lookup: National Student Clearinghouse. |
| Published researcher | Publication record on ORCID or the journal itself, matched to the person by email or institution. Lookup: ORCID. |
| Olympiad or competition medalist (math) | Results lists published by the competition. Useful for math problem-writing work. |
| Physician (MD or DO) | License and any board actions in each state, through the state medical board or DocInfo. Lookup: DocInfo (Federation of State Medical Boards). |
| Board-certified specialist | Board certification status through the ABMS lookup. Lookup: Certification Matters (ABMS). |
| Registered nurse | License status through Nursys, which covers most US boards of nursing. Lookup: Nursys. |
Languages: how wide is the bench?
For multilingual work the first published number is reach. TELUS Digital claims a contributor community of more than one million across 500+ languages. Surge AI says it operates in over 70 languages. Toloka, Appen, Centific and Innodata also sell multilingual data services but give no language count on the pages we read.
Reach is not depth. A vendor with hundreds of languages may have only a handful of people who can grade legal or medical text in a given one, so ask for the number of qualified reviewers in your language pair and field.
| Credential asked for | How to check it yourself |
|---|---|
| Certified translator | ATA certification for the language pair, listed in the association directory. Lookup: American Translators Association directory. |
| Native speaker with domain skill | A graded sample in the target language, reviewed by a second native speaker. |
Disclosure: any vendor in this section could pay us should an introduction we make end in a contract. That has no bearing on how we describe it.
What do vendors publish about vetting and pay?
Vetting: mostly a claim, rarely a method
Of the 15 expert data vendors we checked, none publishes a step-by-step credential process on the pages we read. One shows security certifications: Kili Technology cites SOC 2 Type II plus ISO 27001 when you look at its pricing. Those cover how data is handled, not who the experts are.
So the check falls to the buyer: ask which registries the vendor uses, how often it re-checks, and what share of applicants it rejects. Credential checks by vendor and field.
Pay: three published reference points
- Prolific minimum$8/hr
- Prolific recommended$12/hr
- Alignerr (Labelbox) topup to $150/hr
These are what people are paid, not what a buyer pays: platform fees, management and review sit on top. Prolific's figures are for research participants in general, not credentialed experts. Price a project turns hours into a rough budget.
What should a buyer settle before signing?
Who owns the output. Experts usually sign over their work to the vendor, and the vendor assigns it to you. Ask to see both links in the chain, and whether the vendor can reuse your prompts, rubrics or graded items for other clients.
Exclusivity. It costs more. Among people Epoch AI interviewed about RL environments, the rule of thumb was that exclusivity multiplies the price four- or fivefold. Those are interview estimates, not contract terms, but expect a premium for any work the vendor cannot resell.
Who the experts are, by name or by count. Ask for the number of qualified people in your field, their locations, and how many will work on your project. Small benches become bottlenecks.
Quality you can measure. Agree an acceptance rate against your rubric before production, and who pays for rework.
Our limits. Every price or pay figure here is something a vendor published, shown with the date we saw it; none is a quote for your project. We have not tested or audited any vendor.
How does an expert data project usually run?
Scope and rubric
You define the task, the output format and a rubric. The vendor proposes a credential bar and a bench size.
Paid pilot
A small round, often a few hundred items, graded by your team. This is where most vendor comparisons should happen.
Calibration
Experts and reviewers align on the hard cases. Agreement between graders is measured and the rubric tightened.
Production
Work delivered in rounds on a schedule with a second-pass review and an acceptance rate you can audit.
Questions about expert data vendors
What is an expert data company?
A vendor that recruits people with professional credentials (engineers, attorneys, accountants, scientists, physicians, translators) to write demonstrations, rank model answers, build rubrics and grade outputs for AI training and evaluation. Most sell a managed service; a few run marketplaces where you manage the experts yourself.
Do expert data vendors publish prices?
Almost none publish a price to buyers. Of the vendors on this site, none lists a per-item or per-hour price for a managed expert project; they quote per project. A few publish what experts or participants are paid, which is a floor for your budget, not a price. See price a project.
How do vendors check that an expert is really a lawyer or a doctor?
Most vendors say they vet experts but do not publish the steps. Licenses for attorneys, CPAs, physicians and nurses can be checked on public registries, so ask the vendor which ones it uses and whether it re-checks good standing. Our credential checks page lists the registries by field.
Which vendor is best for coding data?
It depends on whether you need demonstrations, code review, or tasks with automated verifiers. Appen lists 500 coding tasks paired with automated verifiers; Surge AI, Toloka and Turing describe verifiers or RL environments more broadly; most others name code as one field among many. A short pilot graded against your rubric settles it faster than any ranking.
Can medical experts work on a project without patient data?
Yes, and that is the only kind of medical work this site covers: physicians and nurses writing or grading answers to clinical questions, building rubrics and reviewing model outputs, with no patient records involved.
Is the introduction free?
Buyers pay nothing. The site earns its keep from vendors: once an introduction turns into a signed contract, that vendor may owe us a fee.
Where these figures come from
- surgehq.ai (Surge AI) (page checked November 7, 2026)
- turing.com (Turing) (page checked November 7, 2026)
- appen.com (Appen) (page checked November 7, 2026)
- toloka.ai (Toloka) (page checked November 7, 2026)
- micro1.ai (micro1) (page checked November 7, 2026)
- snorkel.ai (Snorkel AI) (page checked November 7, 2026)
- mercor.com (Mercor) (page checked November 7, 2026)
- telusdigital.com, AI training data solutions (TELUS Digital) (page checked November 7, 2026)
- Prolific help center: how payment works for researchers, dated July 17, 2026 (page checked November 7, 2026)
- alignerr.com/about (Labelbox’s expert network) (page checked November 7, 2026)
- "An FAQ on reinforcement learning environments", Epoch AI Gradient Updates, January 12, 2026 (page checked November 7, 2026)
Get a quote
About two minutes, in three parts: company ZIP code, your work email, then some taps describing the task. A person reads every brief.
Describe the project in words only. No datasets, prompts, samples or files, here or by email.
Plain terms: we run an introduction service, and a vendor we introduce could pay us for it.
Brief received.
- We set your brief beside what each expert data vendor publishes about fields, credentials and minimums.
- Our email back names one vendor and says why. At that stage your brief has gone nowhere.
- Reply yes and we make the introduction by email; from there, scope, price and contract are settled directly by you and the vendor.
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